Television watching for almost 6 & almost 8yo DDs

Wondering if you have set rules in your house? We also have a 16mo DD. Since the new school term, TV watching has been banned during the week as I'd like them to read for fun/draw/play in their downtime.It actually worked well & the complaints were minimal. Last night & this morning I've allowed 30 mins each of 'allowed' programmes of their choice, so essentially they've had an hour. We'll watch X Factor together tonight as they've both seen snippets & love it. What do you all do regarding tv watching?